The invasion-associated type III secretion system of Salmonella enterica serovar Typhimurium is necessary for intracellular proliferation and vacuole biogenesis in epithelial cells

ABSTRACT SigD is translocated into eucaryotic cells by a type III secretion system. In this work, evidence that the putative chaperone SigE directly interacts with SigD is presented. A bacterial two-hybrid system demonstrated that SigE can interact with itself and SigD. In addition, SigD was specifically copurified with SigE-His6on a nickel column.

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Salicylidene acylhydrazide-mediated inhibition of type III secretion system-1 in Salmonella enterica serovar Typhimurium is associated with iron restriction and can be reversed by free iron

FEMS Microbiology Letters ◽

10.1111/j.1574-6968.2009.01847.x ◽

2010 ◽

Vol 302 (2) ◽

pp. 114-122 ◽

Cited By ~ 23

Author(s):

Abigail N. Layton ◽

Debra L. Hudson ◽

Arthur Thompson ◽

Jay C.D. Hinton ◽

Joanne M. Stevens ◽

...

Keyword(s):

Type Iii Secretion ◽

Salmonella Enterica ◽

Salmonella Enterica Serovar Typhimurium ◽

Type Iii Secretion System ◽

Secretion System ◽

Free Iron ◽

Iron Restriction ◽

Type Iii ◽

Serovar Typhimurium ◽

System 1

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InvB Is Required for Type III-Dependent Secretion of SopA in Salmonella enterica Serovar Typhimurium

Journal of Bacteriology ◽

10.1128/jb.186.4.1215-1219.2004 ◽

2004 ◽

Vol 186 (4) ◽

pp. 1215-1219 ◽

Cited By ~ 37

Author(s):

Kristin Ehrbar ◽

Siegfried Hapfelmeier ◽

Bärbel Stecher ◽

Wolf-Dietrich Hardt

Keyword(s):

Type Iii Secretion ◽

Salmonella Enterica ◽

Salmonella Enterica Serovar Typhimurium ◽

Type Iii Secretion System ◽

Secretion System ◽

Host Cells ◽

Effector Protein ◽

Enteric Disease ◽

Type Iii ◽

Serovar Typhimurium

ABSTRACT The Salmonella effector protein SopA is translocated into host cells via the SPI-1 type III secretion system (TTSS) and contributes to enteric disease. We found that the chaperone InvB binds to SopA and slightly stabilizes it in the bacterial cytosol and that it is required for its transport via the SPI-1 TTSS.

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Thioredoxin 1 Participates in the Activity of the Salmonella enterica Serovar Typhimurium Pathogenicity Island 2 Type III Secretion System

Journal of Bacteriology ◽

10.1128/jb.00532-09 ◽

2009 ◽

Vol 191 (22) ◽

pp. 6918-6927 ◽

Cited By ~ 13

Author(s):

Aurel Negrea ◽

Eva Bjur ◽

Speranta Puiac ◽

Sofia Eriksson Ygberg ◽

Fredrik Åslund ◽

...

Keyword(s):

Epithelial Cells ◽

Type Iii Secretion ◽

Salmonella Enterica ◽

Functional Integration ◽

Type Iii Secretion System ◽

Pathogenicity Island ◽

Secretion System ◽

Type Iii ◽

Serovar Typhimurium ◽

Thioredoxin 1

ABSTRACT The facultative intracellular pathogen Salmonella enterica serovar Typhimurium relies on its Salmonella pathogenicity island 2 (SPI2) type III secretion system (T3SS) for intracellular replication and virulence. We report that the oxidoreductase thioredoxin 1 (TrxA) and SPI2 are coinduced for expression under in vitro conditions that mimic an intravacuolar environment, that TrxA is needed for proper SPI2 activity under these conditions, and that TrxA is indispensable for SPI2 activity in both phagocytic and epithelial cells. Infection experiments in mice demonstrated that SPI2 strongly contributed to virulence in a TrxA-proficient background whereas SPI2 did not affect virulence in a trxA mutant. Complementation analyses using wild-type trxA or a genetically engineered trxA coding for noncatalytic TrxA showed that the catalytic activity of TrxA is essential for SPI2 activity in phagocytic cells whereas a noncatalytic variant of TrxA partially sustained SPI2 activity in epithelial cells and virulence in mice. These results show that TrxA is needed for the intracellular induction of SPI2 and provide new insights into the functional integration between catalytic and noncatalytic activities of TrxA and a bacterial T3SS in different settings of intracellular infections.

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